Wings save the day

For those of you interested in following the video story of the IRS installation, Part 1 is available for viewing here:http://youtu.be/VOmyHGzG_lI This shows the delivery of the beasts and the teardown of the old music room. What's the old saying about being on a "wing and a prayer"? The designers of the Infinity IRS dipole loudspeaker system had a problem on their hands when they created this beast- it went down in frequency low enough to cause cancellation problems between the back and the front out of phase audio signals. Cancellation on a dipole doesn't really come into play at higher frequencies because high frequencies are very direct and have short wavelengths - short enough to no wrap around the speaker from front to back and cancel - but as the frequency of the sound gets lower and lower, the problem of cancellation gets worse and worse. Take a look at the front loudspeakers in this picture of the 30 plus year old Infinity IRS loudspeaker. Note the big wings (as they were called) which are basically inch thick wood with sand inside of them to keep them inert. Their function was to make a "wall" between the front and the rear radiating speakers - which are out of phase with each other. Designed to look cool by Cary Christie, their real function was to be able to properly launch the low frequency midbass from the EMIM midranges and prevent that out of phase energy from the rear from wrapping around too quickly and reducing output in this all important region. There are certainly other ways to handle rear wave cancellation of a dipole, but this first classic speaker approach was a brute force wall that simply worked and defined the look of this loudspeaker for all time. Truly form followed function in this classic.